Three-dimensional sheet materials which include a thin layer of pressure-sensitive adhesive protected from inadvertent surface contact, as well as methods and apparatus for manufacturing them, have been developed and are described in detail in commonly-assigned patents, Hamilton et al., U.S. Pat. No. 5,662,758, entitled “Composite Material Releasably Sealable to a Target Surface When Pressed Thereagainst and Method of Making”, Hamilton et al., U.S. Pat. No. 5,871,607, entitled “Material Having A Substance Protected by Deformable Standoffs and Method of Making”, McGuire et al., U.S. Pat. No. 5,965,235, entitled “Three-Dimensional, Nesting-Resistant Sheet Materials and Method and Apparatus for Making Same”, and Hamilton et al., U.S. Pat. No. 6,194,062, entitled “Improved Storage Wrap Materials” and McGuire et al., U.S. Pat. No. 6,193,918, entitled “High Speed Embossing and Adhesive Printing Process and Apparatus”.
While the processes and equipment for manufacturing such pressure sensitive, adhesive-coated materials described in these patents are suitable for manufacturing, the nature of the processes and equipment can be sensitive to the materials used in the different machine components. Said differently, individual components of the process may cause problems in the production of pressure sensitive, adhesive-coated materials. One example of this is the embossing rolls used in the prior art processes. These are typically engraved steel rolls coated with a thin release coating (typically less than 2 thousandths of an inch). These coatings are necessary on steel rolls to provide release of the adhesive. While these prior art rolls are suitable for use in the prior art processes, they are less than ideal. In use, the coatings on the rolls are subject to chipping, delamination and abrasive wear resulting in typical coating lifetimes of less than 50 hours. As a result of this deterioration of the roll coating, the rolls cause quality and/or downtime problems from either web tears or pinholes in the adhesive-coated materials. Pinholes occur either due to a sharp edge on an abrasion or from pinching of an abraded edge between the second and first roll. Pinholes reduce the barrier properties of the film and large pinholes can result in fluid leakage. This premature roll coating wear must be corrected by a more frequent replacement of the rolls on the production line.
Replacing the rolls are difficult as well. The high temperatures involved in the recoating of the rolls can result in coatings with poor repeatability making it difficult to qualify new rolls. Also, new rolls are typically made by a mill engraving process which is time-consuming and expensive.
All of these factors result in a significant reduction of reliability and efficiency at which the process and apparatus can be operated, and the reliability and efficiency of such processes and apparatus are is a major factor in the economics of producing such materials on a commercial scale.
Accordingly, it would be desirable to provide a patterned element which has superior durability, and as a result minimizes or eliminates web tears and pinholing, and has good repeatability.